Effective\nAdsorption of Cyclohexene and Analytically\nPerfect Separation of Cyclohexene/Cyclohexanol Azeotropes by Nonporous\nAdaptive Crystals of a Hybrid[3]arene

Cyclohexene is an important volatile organic compound\n(VOC), which\nis the key raw material for the preparation of cyclohexanol. Because\nof the formation of azeotropes between cyclohexene and cyclohexanol,\nthe separation of cyclohexene and cyclohexanol is extremely challenging.\nHowever, there are some challenges for conventional separation methods,\nsuch as complex equipment, high operating costs, and huge energy consumption.\nHerein, we present an energy-efficient adsorptive separation method\nto effectively adsorb cyclohexene and selectively separate cyclohexene\nfrom cyclohexene and cyclohexanol azeotropes with a purity of 100%\nusing nonporous adaptive crystals of a hybrid[3]arene <b>H</b> (<b>H</b>α). As revealed by the single crystal structure,\nmultiple noncovalent interactions between <b>H</b> and cyclohexene\nare responsible for the perfect selectivity. Density functional theory\ncalculations explain in detail the mechanism of the preferential adsorption\nof cyclohexene and the selective separation of cyclohexene and cyclohexanol\nazeotropes by <b>H</b>α. Moreover, the recovery and recycling\nof <b>H</b>α by dissolving <b>H</b>α that\nadsorbed cyclohexene in ethanol are reported for the first time. It\nis anticipated that this work will provide valuable and timely insights\nfor the separation of azeotropes by nonporous adaptive crystals and\nthe interpretation of selective separation using theoretical calculations.